Grammar Syntax

Speech Recognition Grammar Specification (SRGS) consists of two syntaxes for defining grammars:

• Augmented Backus-Naur Form (ABNF).

• Grammar Extensible Markup Language (GrXML)

Interaction Speech Recognition supports both syntaxes in grammar files.

SRGS uses Semantic Interpretation for Speech Recognition (SISR) v1.0 for semantic interpretation.

Example ABNF grammar file

The ABNF syntax uses symbols, words, and operators; much like a scripting or programming language.

// Header
#ABNF 1.0;
language en-US;
mode voice;
// Root rule 
root $yesorno;
// Rules
$yes = yes | correct | yeah | affirmative;
$no = no | nope | negative;
$yesorno = $yes | $no;

To ensure that you can easily identify ABNF grammars when browsing a file system, use the .gram file name extension.

Example GrXML grammar file

The GrXML syntax uses elements and pairs of elements defined within angle bracket characters (< >).

<!--Header-->
<?xml version="1.0"?>
<grammar xmlns="http://www.w3.org/2001/06/grammar"
xml:lang="en-US"
root="yesorno"
mode="voice">
<!--Rules-->
<rule id="yesorno">
<one-of>
<item><ruleref 
 uri="#yes" /></item>
<item><ruleref 
 uri="#no" /></item>
</one-of>
</rule>
<rule id="yes">
<one-of>
<item>yes</item>
<item>correct</item>
<item>yeah</item>
<item>affirmative</item>
</one-of>
</rule>
<rule id="no">
<one-of>
<item>no</item>
<item>nope</item>
<item>negative</item>
</one-of>
</rule>
</grammar>

To ensure that you can easily identify GrXML grammars when browsing a file system, use the .grxml file name extension.

For more information about the SRGS specification and how to create grammars, see http://www.w3.org/TR/speech-grammar/.